math problems

[tyrannix]

google > me for now

so im looking at other options, if my crank doesnt work out.

the tomei 2.0l 'stroker kit' parts (also the only ones available now, normal ones arent)

88mm stroke with the tomei crank89mm bore with the pistons

now, with just the pistons on a ca18, its supposed to increase the displacement to 1852ccand with both crank and pistons, to 2.0l ... on a ca18 block

so im trying to figure out the math do get the actual displacement (and after that maybe CR) if this crank and pistons were stuck in a ca20 block (20mm taller)

(its around $3700 for all 3 items, crank rods and pistons from them :\ )

i emailed takakaira about some stuff, but havnt got a reply yet

ive got the equation partly figured out, i need a math check tho

2000cc + ( 20mm* 89mm* pi ) thats a quick math-out, but it cant be that easy... i know im missing something

CJ

[c-rad]

If you use 89mm bore pistons on a CA, then the total volume would be--

V = pi * (r^2) * hV = 3.14159 * (4.45cm(bore)^2) * 8.36cm (stroke)V = 3.14159 * (19.8025) * 8.36V = 520.09ccV x 4cyl = 2080.36cc

Which doesn't seem right at all. You sure you aren't looking at the SR piston size? 6mm is a lot to bore out of each cylinder.

Compare this to the stock CA--V = 3.14159 * (4.15cm(bore)^2) * 8.36cm(stroke)V = 3.14159 * 17.2225 * 8.36V = 452.32644 x(4cyl) = 1809.31cc

[tyrannix]

thats what i was thinking too, but takakaira only lists 89mm. i seem to remember a bit ago that they carried 2 sizes. but these are listed as matching to the 'stroker' crankshaft (which im waiting on a reply from tehm about to see if it is fully counterbalanced, the description might say otherwise)

but yeah, totally blanked on the equation for volume od a cylinder, thought it was diameter * pi * height (was trying to take a rectangular prism formula and make it round)

so your equations:V = pi * (r^2) * hV = 3.14159 * (4.45cm(bore)^2) * 8.36cm (stroke)V = 3.14159 * (19.8025) * 8.36V = 520.09ccV x 4cyl = 2080.36cc

and ill add the extra 20mm height for the CA20 block

V = pi * (r^2) * hV = 3.14159 * (4.45cm(bore)^2) * 8.36cm (stroke)V = 3.14159 * (19.8025) * 8.36V = 520.09ccV x 4cyl = 2080.36cc------------------------V2 = pi * (r^2) * hV2 = 3.14159* (4.45(radius of bore) ^2) * 2cm (extra height)V2 = 3.14159 * (19.8025) * 2V2 = 124.42ccV2 X 4cyl = 497.68cc

X = V + V2X = 2080.36cc + 497.68ccX = 2578.04cc

please tell me i funked something up?if not, and i use those pistons, it will be almost square again, and be just under 2.6l

holy crap

somebody check me, im almost scared that i am correct on it

keep in mind, this is a supposed stroker kit for a 1.8l, to make it 2l, but to use it on a CA20 block which is 2cm taller

if i am right, this could be a rediculous engine, with low down torque, spooling a bigger turbo up faster, and still able to rev (maybe even close to the same as stock, being back to almost square)

CJ

[tyrannix]

DOH, didnt include the 88mm stroke on teh new crank

going from 83mm to 88mm on the stroke, in addition to the other changes...

but wouldnt it only add half of the difference to the total displacement (because the other half of the stroke is compressing it more)

so to add .25 to the first equation... that seems ok, but it would put it well over 2.6l

V = pi * (r^2) * hV = 3.14159 * (4.45cm(bore)^2) * 8.61cm (stroke)V = 3.14159 * (19.8025) * 8.61V old = 520.09ccV new = 535.64V x 4cyl = 2142.56cc

V2 X 4cyl = 497.68cc

X = V + V2X = 2142.56cc + 497.68ccX = 2640.24cc

yeah, im probably all messed up on the math. but if im not, the possible outcome is scary

CJ

[c-rad]

DOH, didnt include the 88mm stroke on teh new crank

going from 83mm to 88mm on the stroke, in addition to the other changes...

but wouldnt it only add half of the difference to the total displacement (because the other half of the stroke is compressing it more)

so to add .25 to the first equation... that seems ok, but it would put it well over 2.6l

V = pi * (r^2) * hV = 3.14159 * (4.45cm(bore)^2) * 8.61cm (stroke)V = 3.14159 * (19.8025) * 8.61V old = 520.09ccV new = 535.64V x 4cyl = 2142.56cc

V2 X 4cyl = 497.68cc

X = V + V2X = 2142.56cc + 497.68ccX = 2640.24cc

yeah, im probably all messed up on the math. but if im not, the possible outcome is scary

CJ

Thing is, bore x stroke determine the displacement. You need a crank/rod combo that allows the piston to reach the top of the cylinder. Because the CA20 block is 20mm higher, you need a combo that will utilize it. You don't want the piston stopping almost an inch below the combustion chamber. Car would probably run like crap.

[tyrannix]

ok, then as Fraz said (and i completly blanked on) thats why the longer rods are needed (150mm)

and with that comes this:

V = pi * (r^2) * hV = 3.14159 * (4.45cm(bore)^2) * 8.8cm (stroke)V = 3.14159 * (19.8025) * 8.8V = 547.46ccV x 4cyl = 2189.84cc

MUCH more reasonable, an almost 2.2l difference....

but leaves me with the question, then what is the difference between using an 18 block with short rods, or a 20 block with longer rods (except the 20 block needs less machining for teh crank to fit, but more machining to make it DOHC compatible)

and that crank + piston combo is the tomei stroker kit, supposed to be 2.0l ... where did i funk up the math this time?... on second thought, thats exactly what the CA20 is, its a 1.5mm bigger bore, and a longer stroke than a CA18.

BUT not as much

i think im going too far into it and confusing myself now

but a ca22 would be great, just to be able to document it and see what happens

CJ

edit> upon further thought, and the fact that the website says 89.0mm piston = 1852cc, whereas when mathed out, it turns out over 2000, im more inclined to think that the diameter of the piston is messed up, but the displacement would be correct, so ill go backwards and figure what it should be
Modified by tyrannix at 3:02 PM 7/27/2006

[tyrannix]

V = pi * (r^2) * hV = 3.14159 * (4.45cm(bore)^2) * 8.36cm (stroke)V = 3.14159 * (19.8025) * 8.36V = 520.09ccV x 4cyl = 2080.36cc

reverse to find what the bore 'should' be if the displacement number is correct

V x4cyl = 1852ccV = 463cc463cc = 3.14159 * (X(bore)^2) * 8.36cm463=26.2637X^2X=4.19868bore= 4.19868 *2bore= 83.97 mm

thats entirely plausable, an 84mm piston, too bad a ca20 already has a 84.5mm bore :\ but good for ca18 blocks

so unless i can find some 84.5-86 tomei pistons somewhere, no tomei for me

but, please somebody check my math, and you guys with tomei hookups, what sizes of pistons can you get?

looks like ill probably be using pistons made for a honda now

[mbmbmb23]

looks like ill probably be using pistons made for a honda now

If I'm not mistaken there are shops that will build you custom pistons if you give them all your measurements. I remember seeing a website (CP maybe?) where you had to enter all your specs and they would send you a quote after you submitted it.

Just an idea.

-M

[float_6969]

I can GARUNTEE you that you'll never get 89mm pistons in that block. At least not with any sort of cylnder wall that will support boot and not split/distort.

And as far as pistons and rods are concerned, I wouldn't be worried about that part of it AT ALL. All of the places that make forged pistons can make custom pistons. Mine were custom and ran me $600. Expect to spend that same amount on custom forged rods. If you've got a CA20 block, and can get a CA18 stroker crank, the rest is childs play man.

[tyrannix]

I can GARUNTEE you that you'll never get 89mm pistons in that block. At least not with any sort of cylnder wall that will support boot and not split/distort.

no ****, huh

i was waiting for your input, but not on that. the 89mm is obviously a mistake, as the displacement listed nexto it is 185x something. i do remember them having 2 different sizes for CAs

did you read all the equation posts ?

this thread was almost a math based stream of consiousness.

i am just waiting on input from anyone who has already put bigger pistons in (or experience putting bigger pistons in a 4cyl) and/or running a standalone

im trying to extract a sheared bolt to get the FMIC mounted, and i forgot what i was really trying to find out with this thread.... maybge ll remember tomorrow

CJ

[float_6969]

I guess I'm missing what you're wanting to know.

I have bigger pistons in my motor.

I have standalone.

What is it that you want to know looser!?!?!

Heheheh